The proposed work will attempt to establish the immunological parameters necessary for reconstituting guinea pigs immune system in attempts to reject syngeneic lethal line-10 tumor transplants. Cellular lysates from peripheral blood leucocytes will be prepared from hyperimmune baboons xenografted with line-10 or line-1 guinea pig tumors. As tumors develop, the tumored guinea pigs will be treated with xenogeneic anti-line-10 baboon lysates, anti-line-1 lysates, and "normal" lysates from unimmunized baboons. Successful immunotherapy of line-10 tumors will be followed by manipulating dosage schedules, time course of treatment, and in vitro assessment of specific cell-mediated immunity in treated animals. The lysates will eventually be subjected to fractionation, dialysis, and phenol extraction to isolate the biologically active anti-tumor moiety, i.e., ribonucleic acid, protein, nucleoprotein.